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Identifying Features in Optical Spectra Yusra AlSayyad Journal Club 5/20/11.

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Presentation on theme: "Identifying Features in Optical Spectra Yusra AlSayyad Journal Club 5/20/11."— Presentation transcript:

1 Identifying Features in Optical Spectra Yusra AlSayyad Journal Club 5/20/11

2 Game plan Stars – Basic – Exotic HII Regions Galaxies Quasars, Blazars, Seyferts Oh My We play: Identify that Spectrum!

3 Basic Boring MS Stars Look For: – Balmer Series H-α 6563 H-β 4861 H-γ 4341 H-δ 4102 Balmer break 3646 – CaII K,H – HeI – TiO

4 Useful website:

5 What is this?

6 M6: Flare vs. Quiescence Hilton 2010

7 White Dwarfs and Subdwarfs Sayres et al 2010 DA DC

8 WD / M Dwarf Binary Silvestri, Hawley, Szkody 2004

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10 HII Regions Slide Credit: Dalcanton ASTR541

11 Basic Boring Galaxies Mo, Van den Bosch, White

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14 Quasars (QSOs) Mo, Van den Bosch, White

15 Active Galaxies

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17 Identify this Spectrum Questions: 1)What is this? 2)Label Lines? 3)What redshift? Questions: 1)What is this? 2)Label Lines? 3)What redshift? [OII] (3727) Hβ 4861 [OIII](4959, 5007) Hα +[NII] (6563, 6583) [SII](6716, 6731) We see: *Balmer and Forbidden emission lines *Redshift! We see: *Balmer and Forbidden emission lines *Redshift! Calculate Redshift: 1 + z = λ obs /λ em Eg. 7380/6563 = 1.12 => z = 0.12 Calculate Redshift: 1 + z = λ obs /λ em Eg. 7380/6563 = 1.12 => z = 0.12

18 Identify this Spectrum Questions: 1)What is this? 2)Label Lines? 3)What redshift? Questions: 1)What is this? 2)Label Lines? 3)What redshift? SIV/OIV 1400 CIV 1549 [CIII 1909 MgII 2796 Look at wavelength ratios: Ly-α 1216 SiIV/OIV 1400 CIV – 1549 (doublet) CIII – 1909 MgII – 2798 (doublet) Lya/CIV = 0.8 CIV/CIII = 0.8 CIV/MgII = 0.55 Look at wavelength ratios: Ly-α 1216 SiIV/OIV 1400 CIV – 1549 (doublet) CIII – 1909 MgII – 2798 (doublet) Lya/CIV = 0.8 CIV/CIII = 0.8 CIV/MgII = /6000 = /8800 = 0.55 Broad Emission Lines = Quasar

19 Identify this Spectrum Questions: 1)What is this? 2)Label Lines? 3)What redshift? Questions: 1)What is this? 2)Label Lines? 3)What redshift? SIV/OIV 1400 CIV 2549 CII 1909 MgII 2796 Calculate Redshift: Eg. 6000/1909 = 3.14 => z = 2.14 Calculate Redshift: Eg. 6000/1909 = 3.14 => z = 2.14 Look at wavelength ratios: Ly-α 1216 SiIV/OIV 1400 CIV – 1549 (doublet) CIII – 1909 MgII – 2798 (doublet) Lya/CIV = 0.8 CIV/CIII = 0.8 CIV/MgII = 0.55 Look at wavelength ratios: Ly-α 1216 SiIV/OIV 1400 CIV – 1549 (doublet) CIII – 1909 MgII – 2798 (doublet) Lya/CIV = 0.8 CIV/CIII = 0.8 CIV/MgII = 0.55

20 Identify this Spectrum Questions: 1)What is this? 2)Label Lines? 3)What redshift? We See Emission lines (Narrow, Hα at 6563) We don’t see The Hβ + [OIII] triplet pattern Not an HII Region Not a starburst galaxy Not a quasar We See Emission lines (Narrow, Hα at 6563) We don’t see The Hβ + [OIII] triplet pattern Not an HII Region Not a starburst galaxy Not a quasar It’s a cataclysmic variable H-δ 4102 H-γ 4341 H-β 4861 H-α 6563

21 Identify this Spectrum Questions: 1)Which is this? 2)Label Lines 3)Estimate T of continuum (T =.29(cmK)/λ max ) 4)What is the continuum opacity? H-δ 4102 H-γ 4341 H-β 4861 H-α 6563 WE SEE: Broad absorption lines BB continuum WE SEE: Broad absorption lines BB continuum First/SpecificGeneral VegaStar A0V BetelgeuseStar M2Iab SunStar G2V Sirius BWhite dwarf (DA) Gl229BBrown dwarf (T7p) ArcturusStar K2III RR LyrF5 (RRLyr) First/SpecificGeneral VegaStar A0V BetelgeuseStar M2Iab SunStar G2V Sirius BWhite dwarf (DA) Gl229BBrown dwarf (T7p) ArcturusStar K2III RR LyrF5 (RRLyr) UV CetFlare star

22 Identify this Spectrum Questions: 1)Which is this? 2)Label Lines 3)Estimate T of continuum and the line source 4)What is the continuum opacity? Ca H& K H-δ 4102 H-γ 4341 H-β 4861 H-α 6563 WE SEE: Star WE SEE: Star First/SpecificGeneral VegaStar A0V BetelgeuseStar M2Iab SunStar G2V Sirius BWhite dwarf (DA) Gl229BBrown dwarf (T7p) ArcturusStar K2III RR LyrF5 (RRLyr) First/SpecificGeneral VegaStar A0V BetelgeuseStar M2Iab SunStar G2V Sirius BWhite dwarf (DA) Gl229BBrown dwarf (T7p) ArcturusStar K2III RR LyrF5 (RRLyr) UV CetFlare star

23 Identify this Spectrum Questions: 1)Which is this? 2)Label Lines 3)Estimate T of continuum and the line source 4)What is the continuum opacity? WE SEE: Balmer Emission! M star continuum WE SEE: Balmer Emission! M star continuum First/SpecificGeneral VegaStar A0V BetelgeuseStar M2Iab SunStar G2V Sirius BWhite dwarf (DA) Gl229BBrown dwarf (T7p) ArcturusStar K2III RR LyrF5 (RRLyr) UV CetFlare star

24 Summary Look for: – Emission/Absorption – Lines Broad vs. Narrow – Lines Forbidden vs. Permitted – Redshifted? (Hα, 4000Å break) – Continuum Shape

25 Reference: Continuum Opacities

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28 SDSS annotated Spectra for select objects in identification exercise above.


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